A coalition is to be formed to ensure Solomon Islands MPs are held to account over how they spend their constituency development funds.

New legislation is expected to give the MPs a 12 fold increase in the discretionary funds, which are often referred to as slush funds.

A petition to Parliament this week calling for a deferral as the legislation was being debated, failed, but Transparency Solomon Islands says it and other groups will continue their watch dog role.

Its spokesperson, Daniel Fenua, says they are concerned the MPs will not spend the money wisely.

He says communities will be asked to monitor their MPs and report questionable spending.

And he says TSI will work with others who want greater accountability and transparency.

"There are interested groups in the society that are serious about making sure this money is spent in a transparent way, so we will form a coalition and then we will try to make sure that this money, every time the politicians get the money they have to spend it in a more transparent and accountable manner."